Assessing the UV-pulse-laser-induced damage density of fused silica optics using photo-thermal absorption distribution probability curves

A photo-thermal absorption distribution probability curve based on a normal distribution model was proposed to describe the distribution of absorptive defects on fused silica surfaces under different processing conditions. Simultaneously, the maximum distribution probability absorption coefficient (MPA) and absorption distribution deviation (ADD) were used to quantitatively describe the overall absorption level and the uniformity of the absorption distribution on the fused silica surface. Based on this, the MPA (μ) and ADD (δ) were used to establish a statistical numerical relationship with the surface damage density of fused silica. The results showed that when μ ≤ 0.095 ± 0.015 and δ ≤ 0.045 ppm, the fused silica optics met the manufacturing process requirements for high laser-induced damage performance. Thus, a non-destructive approximate evaluation of the laser-induced damage density on the fused silica surface was achieved. This evaluation method provides a new, to the best of our knowledge, technology for evaluating the manufacturing process quality related to the damage performance of fused silica optics in high-power solid-state laser facilities and is an important supplement to popular destructive laser-induced damage testing methods.